A model of oxide layer growth on Ag+ and Pt+ ion implanted nickel anode in aqueous alkaline solution

Abstract

This work investigates nickel oxide films growth on nickel implanted with ions of the noble metals Ag and Pt. Polycrystalline and single crystal samples of Ni were implanted with high fluences (1x10^19–1x10^21 m^(–2) of 9–50 keV ions. Galvanostatic and potentiostatic polarization techniques were applied to monitor the electrochemical efficiencies of formation of NiXO1–X films in aqueous KOH solution (30%) at 353 K. The growth rates, thickness and compositional profiles of oxidised nickel layers were examined by means of RBS. It was found that the anodic oxide film consists of Ni(OH)2XH2O (X≥1). Anodic oxidation of nickel occurs due to out-diffusion of Ni atoms through the hydroxide layer. Implanted Ag penetrates partly into the anodic oxide whereas platinum is completely buried beneath the oxide film.